Older people who load up their plates with carbohydrates have nearly four times the risk of developing mild cognitive impairment, a study released Tuesday finds.
Sugars also played a role in the development of MCI, a precursor to Alzheimers disease, according to the report in the Journal of Alzheimers Disease. Eating more proteins and fats offer some protection from MCI.
Mayo Clinic researchers tracked 1,230 people ages 70 to 89 and asked them to provide information about what they ate the previous year. Among that group only the 940 people who showed no signs of cognitive impairment were asked to return for 15-month follow-ups. By the studys fourth year, 200 of the 940 were beginning to show mild cognitive impairment, problems with memory, language, thinking and judgment.
Not everyone with MCI goes on to develop Alzheimers disease, but many do, says lead author Rosebud Roberts, a professor in the department of epidemiology at the Mayo Clinic in Rochester, Minn. Alzheimers affects 5.2 million adults in the nation, numbers that are expected to triple by 2050 as the baby boomers age.
The research field is trying to find things that can help reduce risk factors for pre-dementia problems, Roberts says. If we can stop people from developing MCI, we hope we can stop people from developing dementia. Once you hit the dementia stage, its irreversible.
Among the foods regarded as complex carbohydrates: rice, pasta, bread and cereals. The digestive system turns them into sugars. Fruits, vegetables and milk products are simple carbs.
A high-carbohydrate intake could be bad for you because carbohydrates impact your glucose and insulin metabolism, Roberts says. Sugar fuels the brain, so moderate intake is good. However, high levels of sugar may actually prevent the brain from using the sugar similar to what we see with type 2 diabetes.
Roberts says high glucose levels might affect the brains blood vessels and also play a role in the development of beta amyloid plaques. Those proteins are toxic to brain health and are found in the brains of people with Alzheimers. Researchers dont know what causes the disease, but they suspect the buildup of beta amyloid is a leading cause.
Also among the studys findings:
Those whose diets were highest in fat (nuts, healthy oils) were 42 percent less likely to get cognitive impairment, while those who had the highest intake of protein (chicken, meat, fish) had a reduced risk of 21 percent.
Several popular diets, including the Mediterranean (fish, poultry-based protein, and plenty of plant-based foods and healthy fats) and Atkins (low-carb, meat-lovers diet), make pitches for the multiple health benefits derived from lowering carbohydrate intake, including reduced risk for heart disease, diabetes and improved brain health.
© 2012 USA TODAY. All rights reserved.